Field of the Disclosure
The present invention relates to torches for generating electric arcs, and in particular to liquid-cooled welding torches.
Description of Related Art
Conventional liquid-cooled torches for generating electric arcs have a cooling tube or conduit located between the base or handle of the torch and the tip of the torch (from which the electric arc is emitted). The torch is heated by the arc during welding, plasma cutting, etc. To remove the heat from the welding torch, cooling liquid, such as water, is circulated through the cooling conduit. The cooling conduit typically has at least two longitudinal cooling passages extending toward the tip of the torch. One of the passages is used to convey cold water toward the tip of the torch, and the other passage is used to return heated water to a chiller or waste receiver. The passages are often on opposite sides of the cooling conduit (e.g., spaced approximately 180° apart). This can result in undesirable temperature gradients across the cooling conduit, with one side of the cooling conduit near the cold water supply passage being cooler than the other side of the cooling conduit near the warm water return passage. Temperature gradients across the cooling conduit in turn can lead to a slight warping of the cooling conduit due to differing amounts of temperature-induced expansion and contraction of the cooling conduit. Warping of the cooling conduit can result in the tip of the torch being misaligned or out of an expected position, which can decrease the precision of the resulting weld or cut, in particular during robotic control of the torch. Thus, it would be desirable to provide a liquid-cooled torch configured for generally uniform cooling of the cooling conduit, so that the temperature-induced expansion/contraction of the cooling conduit is generally uniform (e.g., around the circumference of the cooling conduit).